import React, { Component } from 'react';

// 规范Props的类型
interface IProps {
  username?: string
  password: string
}

// 规范了state的类型
interface IState {
  count: number
  params: object
}
export default class A extends Component<IProps, IState> {
  render (): JSX.Element {
    const { count, params } = this.state;
    return (
      <div>A</div>
    );
  }
}
